A Rural Subdivision in the Northern

TerritoryNeville L. Brayley LS

April 2015

What does a 2 Lot Subdivision in the NT bush look like?• Large• Hot• Things want to kill or hurt you• There are lots of those things• There are two seasons – the Wet and the Dry – both are hot• 4 wheel driving is a given• Quad bikes are a given• GNSS equipment is a given• Geodesy is relevant (who would ever have thought Rod Deakin’s

dissertations actually mattered in real life?)• It’s large, hot & things really do want to kill you

Large

Similarities• Some jobs like we have in Western & North Western Victoria• A few hundred acres, or maybe a thousand + acres occasionally• Some river boundaries• Some ocean boundaries• They are mostly all bush, not much pasture grazing• In the NT we produce a Survey Plan & a Surveyors Report

LargeDifferences• The wet makes fords, creeks and rivers totally un-passable at times• Sometimes you can’t get to jobs. Or get home!• It can be a very long drive to a job – sometimes all day• A tidal range of about 7 metres• Mangroves and mud flats along the ocean and rivers• Things live in those mangroves – they move quicker than you – and want to

kill you• Stock are mustered with helicopters• Areas are spoken about in square kilometres• Land tenure is often quite different to what we know here• When the client shows you around the job, he does it in his plane!

What is large?

• If a Victorian surveyor had a rural job where one lot was 95ha and the other 112ha, they would consider that a pretty big job

• In the one I have just completed one lot is 95,000ha and the other 112,000ha.• The entire southern boundary is the Daly River – about 50km of river

frontage• And things in it want to kill you

Large

• Tipperary Station• About 250 km south west of

Darwin• Title area is over 2,100 Sq. Km• The size of a small country

Large

The components of the survey• Get all of your survey search• Mobilise• Reconnaissance – plane and vehicle• Construct all of your permanent marks (knowns as CRMs in the NT)• Do the Static network• Do AUSPOS observations (log while doing RTK in excess of 6 hours)• Look for cadastral marks• Cadastral Survey – pick up old marks, posts, new marks, pegging• Comps, reports and plan production

GNSS Equipment – Static Session Planner

GNSS Equipment – Static Observation Key Diagram

GNSS Equipment – Static Logging & Booking Sheet

GNSS Equipment – Network Diagram showing distances

GNSS Equipment – TBC Software Screen Shot

GNSS Equipment – Static & AUSPOSThings to lodge with the Plan to the Surveyor General• Static Logging Sheet• Network Control Diagram• Network Adjustment Report• Adjusted Co-ordinate list – MGA94 and Lats & Longs• Technical Report detailing field and office processes and

demonstrating adherence to regulated accuracy requirements• RINEX data for the static network• RINEX data for the AUSPOS determinations

Geodesy is Relevant

In the NT when doing large jobs two items that Surveyors have to adhere to I find extremely interesting• When pegging a line of Latitude, you MUST put a bend in the line

every 10 kilometres!• When calculating final plan areas you MUST adjust the area using the

Large Area Misclose formula

Geodesy is Relevant

The Final Plan of Subdivision

• This was only a 3 sheet plan• The plan numbering system is different to Victoria's, as is their

method of having multiple sheets in a plan• Nearly all plans are currently drawn at A1• Like Victoria, there are many subtleties relating to the drawing and

presentation methods. But they can be quite different so a whole new learning curve• In rural areas the bearing datum MUST be “True Mid”. There’s that

geodesy stuff again – you get forward and reverse bearing differences on east/west lines. The longer the line, the greater the differences.

The final areas were:•NT Portion 7347 = 95,370 ha•NT Portion 7348 = 112,400 ha

Sheet 2 Created Daly River Road

Sheet 3 was the new boundary. Between the Daly River Road & the Daly River

Sheet 3 was the new boundary. Between the Daly River Road & the Daly River

Surveying Territory Style

all in a hard days yakka

Rural Surveying is heaps of fun

Neville Brayley